Loading...
Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
Browse
102 results
Search Results
ThesisItem Open Access Studies on fertility status of rubber growing soils of Palakkad district(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1991) Mohanan, V; KAU; Nazeem, P AThesisItem Open Access Development of a suitable model for ascertaining the growth and egg production in quails(Department of Agricultural Statistics, College of Horticulture, Vellanikkara, 1991) John Thomas, M; KAU; George, K CAn investigation was carried out into the growth and egg production aspect of Japanese quails at the Kerala Agricultural University Poultry Farm, Mannuthy on 1st February, 1989 with the following objectives. 1. to find a suitable relationship between age and body weight. 2. to investigate the" trend of egg production in quails through suitable mathematical models. ,3. to study the impact of climate parameters (temperature, ; , humidity) on egg production in quails. The birds were reared under uniform feed formula and ^identical management practices (recommended by Kerala Agricul tural University Package of Practices). The investigation mainly depended on' data consisting of weekly body weights of -ii^-dividual birds, daily egg production of birds (beginning from age at sexual maturity) and daily climatological para meters (temperature and humidity) from beginning till the end of experiment of 30th September, 1989. Mathematical models such as linear, quadratic, exponential, .Von-Bertalanffy, modified exponential, logistic and Gompertz were fitted for the purpose using body weights of ) individual birds as well as average body weights over twelve weeks and the fitted models were compared using coefficient of 2 determination (r ) and standard error of estimate(s). Mathematical models such as linear, exponentialf parabolic exponential, inverse polynomial. Gamma function. Gamma-type functic^n, quadratic function, quadratic function in logari'thmic scale, quadratic-cum-log, emperical and linear hyperbolic functions were fitted for the development of suitable models for ascertaining egg production using total weekly, fortnightly egg production, hen housed and hen day egg production and fitted models were compared using Furnival index, r^ and s. Multiple linear regression equation was fitted using average weekly egg production per bird as dependent variable and weekly temperature and humidity as explanatory variable to study the impact of climatological parameters on egg production in quails. The investigation has the following, salient features. (i) The hatching weight of Japanese quails were 7.1369 g. (ii) The females weighed more than the males during the entire period of experiment and the body weights have shown an increasing trend. At the end of 12th week the average body weights of males and females were 157.6552 g and 179.2500 g respectively. (iii) Rao's method justified that initial body weights • had no significant effect on growth rate. • (iv) Gompertz curve = a exp [-b exp(-kt)'] was most , suitable for , ascertaining growth in quails on individual basis as well as on the basis of • average body weights over twelve weeks. (v) Average age at sexual maturity (females) was found to be approximately 10 weeks and on an average the eggs weighed 12.20 g. (vi) Quadratic function in logarithmic scale ; = a f b(logJ^) + c(log^)^ was most suitable , for ascertaining egg production in quails (weekly, , fortnightly, hen housed and hen day production • basis). (vii) Climatic parameters had significant impact on egg production in quails.ThesisItem Open Access Biology and biometry of Neochetine elchhorniae warner (Curculionidae: Coleoptera) and the nature of damage caused by it on Eichhornia crassipes (mart)(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1990) Sreekumar, K M; KAU; Joseph, DThe biology, morphology, biometrics and dispersal pattern of the weevil Neochetina eichhorniae Warner and the nature and extent of damage caused by it on water hyacinth (Eichhornia crassipes (Mart.) were studied. An indirect method of estimating the field population was also attempted. The insect laid the eggs beneath the epidermis of plant parts. Incubation period was 6.6 days and the hatching percentage was 93.2. The larvae fed by tunnelling, and the first, second and third larval instars were completed in 8-10, 13-16 and 13-17 days, respectively. The cocoon was attached to the live roots of the plant and the pupation was just below the water surface. The pupal period was 16.6 days. Adult female longevity was 75.3 days while that of the male was 172.3 days. Pre-oviposit iona I period was 49 days and the total number of eggs produced during the whole life period was 462.5. The head capsule width of first, second and third instar larvae were 0.3, 0.488 and 0.693 mm respectively. In adult males, the average distance between the antennal socket and the tip of the rostrum was 0.259 mm and it was 0.487 mm in females. This character helps in the identification of sexes. No microbes or mites were recorded as natural enemies. The predators were the common non-specific aquatic insects like dytiscid beetle, giant water bug, dragon fly naiads and back swimmers.ThesisItem Open Access Quantitative analysis of runoff parameters in selected river basins of Kerala(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1990) JJayasree, S; KAU; John Thomas, KThe evolution of a drainage basin is the result of the flow of mass and energy and the resistance of topographical surface. Precipitation is the major source of matter and solar radiation, the source of energy. The stream flow is a function of geomorphological and hydrological factors of the river basin. The objectives of this study were to make a quantitative analysis of the effects of geomorphological and climatic factors on the stream flow and to study the inter – relationships between these factors. The selected river basins were Chaliyar and Kabbani. The specific objective was to express stream flow in terms of morphological factors and rainfall. The river basin was divided in to sub basin, each of which contains a rivergauge station. Morphological factors were measured from the map. Monthly rainfall from all the raingauge stations were collected and the arithmetical average for each sub-basin was computed. The monthly stream flow was also collected. It was found that the morphological factors were interrelated. The number of stream segments of successive order form a decreasing geometric progression whereas the length of stream segments of successive orders form an increasing geometric progression. Confluence ratio is inversely related to stream flow. Elongation and drainage area are highly correlated. A larger value for the confluence ratio indicates a more elongated basin and a lower flood peak. The sub - basins are similar to the form of a rectangle. Area and elongation are the morphological parameters strongly influencing the stream flow. Drainage density and stream frequency are highly correlated. Drainage density gets altered by the land use, vegetal cover, deforestation and urbanization. Drainage density also affect stream flow. Finally, the expressions for drainage area in terms of the main stream length, drainage density in terms of stream frequency and average monthly stream flow contributed by unit area in terms of the average monthly rainfall were obtained. The data used for the final equation was inadequate. The equation may be improved, by increasing the number of rivergauge stations and providing more representative raingauge stations.ThesisItem Open Access Induced chemical mutagenesis in Rose under in vitro culture(Department of Agricultural Botany, College of Agriculture,Vellayani, 1991) Uma, B; KAU; Krishnan Nair, NThe present investigation entitled “Induced chemical mutagenesis in rose (Rosa chinensis) under in vitro culture” was carried out in the Tissue Culture Laboratory attached to the Horticultural Department, College of Agriculture, Vellayani during 1989-90. The main objectives of the experiment were to standardize a suitable culture medium for the growth and development of axillary buds and to standardize a successful method of chemical mutagenesis in rose under in vitro culture using the most potent chemical mutagen, ethyl methane sulphonate. The standardization of hormone levels in the culture medium (ms) was done at three stages of explant development viz. culture establishment, axillary bud proliferation and in vitro rooting. Surface sterilization of axillary buds were standardized by using mercuric chloride selecting out three concentrations 0.06, 0.08 and 0.1 per cent and 3 periods of treatment 5, 10 and 15 minutes. The axillary buds used were of 4 maturity stages ie. Axillary buds at the time of flower harvest and 2, 4 and 6 days after flower harvest. The various concentrations of ethyl methane sulphonate tested include 0.125, 0.25, 0.375 and 0.5 per cent. Two methods of mutagen treatments were tried ie. direct treatment and cotton swab method. In the direct treatment the axillary buds were subjected to EMS treatment at different periods treating the buds at the time of culturing, 2 days after culturing, 4 days after culturing and 6 days after culturing. In the cotton swab method buds were treated with EMS in the plant itself at various stages ie. at the time of flower harvest and 2,4 and 6 days after flower harvest. Surface sterilization of axillary buds was found to be most successful with mercuric chloride at 0.08 per cent for 15 minutes of the various levels of hormonal combinations tested BAP 2 mg/1 +2.4-D 1 mg/1 was found to be the best for culture establishment and BAP 2 mg /1 +GA 1mg/1 for shoot proliferation. Maximum rooting was obtained in full strength MS medium supplemented with IAA 2 mg/1 of the two methods of mutagen treatments tried direct treatment of axillary buds with EMS was not found to be effective as the buds turned brown and no further development occurred. In the cotton swab method, lower concentrations of EMS (0.125 and 0.25 per cent) gave a better performance based on days taken for bud take multiple shoot production and rooting percentage. A decrease in survival percentage was noted with increase in mutagen concentration. Higher concentration of EMS (0.375 and 0.5 per cent) curbed multiple shoot production in buds excised at the time of flower harvest and delayed multiple shoot production in other stages. The percentage cultures showing rooting and the number of roots/shoot also decreased with increase in concentration of EMS. Increase in maturity of buds also delayed multiple shoot production and decreased rooting percentage of the 4 stages of buds used for in vitro culture, buds excised at the time of flower harvest was found to be the best. But mutagen treatment retarded their performance. For mutagen treatment buds excised 4 days after flower harvest was found to be best followed by buds excised 2 days after flower harvest. Buds excised 6 days after flower harvest showed a poor performance in the normal and treated populations. The experiment clearly demonstrated that induced mutagenesis in rose can be successfully done adopting in vitro culture techniques.ThesisItem Open Access Comparative performance of three exotic tree species in social forestry strip plantation in Trichur Social Forestry Division(College of Forestry,Vellanikkara, 1990) Nandakumar, G; KAU; KrishnanNair, V RA study was conducted in 1987-88 on the social forestry strip plantation on the premises of the Sitaram Textile mills Ltd. In the Trichur Social Forestry Division of Kerala State; to compare the performance of three exotic fast growing tree species, Casuarina equisetifolia, Acacia auriculiformis and Eucalyptus tereticornis in social forestry strip plantation. Comparisons were made on the three year old plantation in respect of growth, biomass production and impact on the soil and undergrowth. General observations were also made on the tree form, occurance of pests and diseases and wild life habitat improvement. The site of experiment was being used for dumping coal cinders and other wastes from the textile mill and was barren before planting. The experiment was laid out in RBD with five replications. The results obtained in the study have been summarised below : At the end of the third year Acacia auriculiformis had a DBH of 4.56 cm followed by Eucalyptus tereticornis with 3.82 cm and Casuarina equisetifolia with 1.62 cm. The mean annual diameter increments were 1.44 cm/year in Acacia, 1.20 cm/year in Eucalyptus and 0.51 cm/year in Casuarina. Acacia had more primary branches (27/tree) followed by Eucalyptus (23/tree) and Casuarina (17/tree). The first primary branch was 3.18 m above the ground in Eucalyptus, 2.22 m in Acacia and in 2.16 m in Casuarina. Acacia had 100% survival at the third year while Eucalyptus had 88%. But Casuarina had only 72% survival rates. In growth as well as survival, Acacia auriculiformis was found to be the best among the three. Eucalyptus tereticornis was found superior to Casusrina equisetifolia while the latter was the least impressive of the three. The total biomass yield at the third year was 98.438 mt (drymatter)/ha in Acacia auriculiformis, 48.424 mt/ha in Eucalyptus tereticornis and 12.506 mt/ha in Casuarina equisetifolia. Acacia had a mean annual biomass increment of 32.813 mt/ha. MAI of Eucalyptus was 16.141 mt/ha while that of Casuarina was only 4.169 mt/ha. In biomass production too, Acacia auriculiformis was found superior to Eucalyptus tereticornis and Casuarina equisetifolia. Of the three species Casuarina equisetifolia with a light intensity on the floor of 49.5% was the least shading one, followed by Eucalyptus tereticornis with 43.6% and Acacia auriculiformis with 30.6%. Eucalyptus was found to permit luxuriant undergrowth, so also casuarina. The above ground phytomass was 1.431 kg drymatter/m2 in Eucalyptus and 1,176 kg/m2 in Casuarina. But Acacia was found to inhibit undergrowth (0.183 kg/m2 ). Even the little undergrowth that was permitted by it comprised mostly of its own seedlings. The undergrowth in Eucalyptus comprised mostly of woody species (65.5%) while that of casuarina comprised mostly of grasses (68.5%). The presence of coal cinders had caused a rise in the soil pH, organic matter content, available Nitrogen content and available phosphorus content of the soil. The lowest pH value in the top soil was found in Acacia soil 4.31. Eucalyptus soil had 4.69 and Casuarina soil had 4.94 compared to the barren laterite (5.16) and the barren laterite with coal cinders (5.32). At the depth of 30-45 cm, the pH values were 4.85 in Acasia soil, 5.17 in Casuarina soil and 5.32 in Eucalptus soil. The barren laterite had a pH of 5.24 and in the barren laterite with coal cinders it was 5.42. The pH at 60-70 cm depth was 4.88 in Acacia soil 5.24 in Casuarina soil, 5.33 in Eucalyptus soil, 5.36 in barren laterite and 5.52 in barren laterite with coal cinders. All the three species reduced the pH of the soil. But Acacia auriculiformis was found to lower the pH of the soil more than the other two. pH increased with the depth in all the treatments. The organic carbon contents in the top soils were 0.57% in Acacia, 0.41% in Eucalyptus, 0.49% in Casuarina, 0.39% in barren laterite and 0.43% in barren laterite with coal cinders. The organic matter content was found to decrease as depth increased in all the treatments. There was a general rise in the organic carbon content of the soils due to the impact of the three species with the maximum in Acacia soils and the minimum in Casuarina soils. The available Nitrogen content in the top soil was 1277 kg/ha in Acacia, 1165 kg/ha in Eucalyptus, 1098 kg/ha in Casuarina, 874 kg/ha in barren laterite and 963 kg/ha in barren laterite with coal cinders. There was a reduction in the available Nitrogen content as the soil depth increased in all the treatments. All the three species caused an increase in the available Nitrogen content of the soil, the highest being observed in Acacia auriculiformis followed by Eucalyptus tereticornis. The available Potash content of the soils did not record any change under the different species. The available phosphorus contents of the top soils were 92.7 kg/ha in Casuarina, 90 kg/ha in Eucalyptus, 81.5 kg/ha in Acacia. 79.3 kg/ha in barren lateric and 87.4 kg/ha in the barren laterite with coal cinders. There was reduction in the content of the nutrient as depth increased in all the treatments. In Acacia soils the content of the available Phosphorus had decreased. Regarding the general observations, Acacia auriculiformis showed pronounced branching habits while Eucalyptus and Casuarina had more or less clean boles. Pests and diseases were not observed excepting the pink disease (c.o. Corticium salmonicolor) in Eucalyptus. Crows and rodents were the principal representatives of wild life in the plantion. Honey bees commonly foraged the inflorescence of Acacia. Acacia auriculiformis proved itself to be a highly promising tree for energy plantations and for afforesting sites dumped with coal cinders and for sites offering little protection from anthropogenic influences and grazing. It also improved the organic matter content and available nitrogen content of the soil and was free from graziers. But at the same time there were also unwelcome effects due to Acacia such as increasing the acidity of the soil and supressing undergrowth. It also tended to be highly branching. Eucalyptus tereticornis also was found to be good in growth and biomass production and could be recommended for similar sites. The species also enriched the soil by increasing the contents of organic carbon and available Nitrogen. Though it too reduced the pH of the soil, the species was found to support luxuriant undergrowth and was spared by graziers. Casuarina equisetifolia was a less suitable species for such a site as seen from the performance of the species. It suffered heavily from browsing and showed lesser survival growth and yield. But the species increased the organic carbon content and available Nitrogen content of the soil and permitted luxuriant undergrowth especially grasses.ThesisItem Open Access Analysis of Maturity related Characters and Identification of Early Maturing Varieties in Groundnut(Department of Plant Breeding, College of Agriculture,Vellayani, 1990) Sunil Kumar, A C; KAU; Sverup JohnWith the intention of identifying suitable superior early maturing genotypes for intensive cultivation in the summer rice fallows of Kerala, a study was conducted for determining the time of optimum physiological maturity of twelve bunch type groundnut genotypes by analyzing the various maturity related component characters in staggered harvests. The twelve test genotypes and the yield and duration checks were staggered harvested at 70, 80, 90, 100 and 110 DAS. The characters that were put to study in each harvest included the height of plant, number and percentage of mature pods, pod yield, 100 pod weight, 100 kernel weight, shelling percentage, percentage of sound mature kernels, haulms yield, harvest index and oil percentage. Analysis of the various parameters in different genotypes indicated that peak pod yield and time of optimum maturity were closely associated with peak performances of components like number of mature pods, 100 pod weight, 100 kernel weight, sound mature kernel percentage and shelling percentage. It was also noted that the genotypes gave fairly high oil percentage at the time of optimum maturity. The genotypes IES 882, IES 883. IES885, ICGS(E) 21, ICGS(E) 52, ICGS(E) 121, Dh(E) 20 and Dh(E) 32 attained optimum physiological maturity at 90 DAS due to attainment of peak values for the various maturity related component characters. A critical appraisal however showed that the genotypes ICGS (E) 52 and IES 883 exhibited significantly superior performance over the remaining genotypes and the yield and duration checks at 90 DAS. The genotypes ICGS (E) 52 and IES 883 may be recommended for intensive cultivation in the summer rice fallows of Kerala owing to realization of high yield and yield attributes, combined with early maturity. ICGS (E) 52 ranked first with a pod yield 12.85 g per plant, 100 pod weight of 88.6 g and 100 kernel weight of 38.1 g. The genotype IES 883 stood second in performance with a pod yield of 12.00 g per plant, 100 pod weight of 88.3 g and 100 kernel weight of 36.2 g. Both the genotypes exhibited appreciably high performance for shelling percentage and sound mature kernel percentage also.ThesisItem Open Access Quality Characters Of Clove And Nutmeg At Different Stages Of Maturity(Department of Horticulture, College of Agriculture,vellayani, 1990) Manoj, A M; KAU; Vasanthakumar, KThe present investigation was carried out at the College of Agriculture, Vellayani during 1988 – 89. The objectives of this study were to characterise the growth pattern of clove flower buds and nutmeg fruits and to develop suitable harvest indices for these crops based on quality characteristics at different stages of maturity. The moisture content in clove buds and rind of nutmeg fruits increased with increase in maturity. However, moisture percentage in nutmeg kernel and mace was found to decrease as maturity advanced. The non – volatile ether extract (NVEE), on dry weight basis, was found to decrease on maturity advanced in clove buds and in mace while in nutmeg kernel the NVEE showed an increasing trend. The volatile oil in clove, nutmeg and mace was more at the immature stages and it progressively decreased at the peak harvesting stages. Eugenol, the chief component in clove oil was the maximum at the flowering stage. Hence for extraction of clove oil which is intended for use in medicine, dentistry and other pharmaceutical uses, it is advisable to harvest clove buds at the anthesis stage. The aromatic ethers which are the chief components that determine the flavour and drug action in nutmeg oil was the maximum one month prior to the fruit splitting stage. In mace oil it was found to be high two months prior to fruit splitting stage. So if nutmeg and mace oils are intended for medicinal purpose, then it may be worthwhile to harvest nutmeg fruits at the 6th month for extracting kernel oil and at the 5th month for extracting mace oil. Considering the fact that the nutmeg fruit yield both nutmeg and mace oil, harvesting separately at different maturity stages for extraction of the different oils is practically difficult. The aromatic phenol and phenol ethers showed a very low value in mace oil one month prior to fruit splitting. So in practice the fruit may be harvested two months prior to fruit splitting for extraction of both nutmeg and mace oils. However the high moisture content at this stage makes drying a problem. So such a practice of early harvesting of nutmeg fruits may be resorted to in places where facilities are available for extraction of oil from the fresh kernel and mace immediately after harvesting.ThesisItem Open Access Biology and Population Build up of the Rice Whitebacked Planthopper, Sogatella furcifera (Horvath) on Different Rice Varieties(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1990) Ajith, P P; KAU; Madhavan Nair, GInvestigations were carried out in the College of Agriculture, Vellayani during 1988 to identify cultivars resistant to the white backed planthopper, S. furcifera from among the high yielding rice varities commonly cultivated in Kerala. The rice cultivars Cul 126, Cul 93, Ptb 33, Karthika, Pavizham, Jyothi, Triveni and TN-1 were chosen for preliminary screening by seed box screening, free-choice and no-choice tests and by tests on orientation and settling response and population build up. In the seed box screening and free choice and no choice tests, the cultivar Cul 126 recorded the lowest damage and the cultivar TN-1 showed the highest damage, indicating resistance in the former and susceptibility in the latter. The cultivar Jyothi did not differ from Cul 126 and the cultivars Cul 93, Ptb 33, Pavizham and Karthika showed intermediate levels of resistance. In the orientation and settling response test the highest number of S. furcifera nymphs were seen settled on TN-1, where as it was the lowest on Cul 126 and it was followed by Jyothi, indicating a clear preference to the susceptible TN-1. The insect multiplied faster and in greater number on TN-1 and the total count was about thirty times more on TN-1 as compared to that on Cul 126 at 60 days after release. Based on the results of the preliminary screening trials, the cultivar Cul 126 and Jyothi (resistant), Pavizham and Karthika (moderately resistant) and TN-1 (susceptible check) were selected for studying the mechanisms of resistance. In the experiment to study the ovipositional preference of the insects it was found that the susceptible TN – 1 and the resistant Cul 126 received the highest and lowest number of eggs respectively. It was also revealed that the leaf sheath received more eggs than the leaf blade. The antibiosis factor in the cultivars was investigated in terms of nymphal duration, nymphal survival, sex ratio of emerging adults, adult longevity, fecundity and hatching percentage of eggs in three growth stages of plants, namely, seedling, tillering and booting stages. The insects from the susceptible TN – 1 had the shortest nymphal duration and the longest adult longevity. The percentage of nymphal survival, fecundity and female/male ratio of the emerging adults were also the highest on TN -1. However, the insects from Cul 126, and Jyothi had longer nymphal duration and shorter adult longevity. The survival, fecundity and female/male ratio of the emerging adults from these cultivars were also lower as compared to TN – 1. The results were uniform in all the three growth stages of the crop. No difference could be observed in the hatching percentage of eggs in the test cultivars in the seedling stage, but in the tillering and booting stages the eggs on TN – 1 showed higher hatching percentage. The results indicated the presence of antibiosis factor in the resistant cultivars, Cul 126 and Jyothi. These results were further confirmed in the experiment on the feeding rate of the insect on the test cultivars. Insects on TN-1 produced the largest area of honey dew spots as compared to others in all the three growth stages showing significantly higher feeding rates. The feeding rate in Cul 126 was the lowest. The effect of crowing of first instar nymphs was more pronounced on the insects on TN-1. The survival percentage was the maximum in crowing at the rate of 25 and it dwindled substantially in the susceptible and resistant cultivars alike in crowding at the rate of 100. Crowding did not have any effect on the sex ratio and brachyptery of emerging adults. When S. furcifera and N. lugens were released together in different proportions, the latter surpassed the former in total number in all the cultivars when counts were taken at 60 days after release of the insects. The result indicated that in cultivars resistant or susceptible to both the insects, N. lugens established a numerical superiority over S. furcifera. In studies to identify the wet land weeds which serve as alternate hosts to S. furcifera, it was found that the insects oviposited in none of the weed plants tested. The nymphs could survive only on Echinochloa colona and Panicum repens.
